Containers for storing and dispensing sterile liquids are known which have an outer or overcap on the bottle neck. Such containers are in common use for various medical and hospital procedures, such as the administration of irrigating solutions.
Such sterile liquid medical containers have a common purpose of maintaining the sterility of their liquid contents during storage, shipping and dispensing. It is necessary that the closure system be easy for the nurse or physician to open, advantageously by the customary continuous counterclockwise rotation of the closure on the container.
One prior art closure for a container having a neck defining a dispensing outlet is disclosed in Choksi U.S. Pat. No. 3,923,182. The closure includes an overcap fitted on the bottle neck closing the dispensing outlet and connected to the bottle neck to define a hermetic seal. The overcap is threaded on its outer surface. An outer ring fits over the overcap and has internal threads engaged with the threads on the overcap. Downward rotation of the outer ring serves to jack the overcap off the bottle neck, breaking the hermetic seal.
Difficulty has been experienced when the nurse or physician turns the outer ring in the wrong direction, removing the outer ring from the overcap without severing the hermetic seal and removing the overcap. In addition, the outer ring may become disassembled from the overcap during handling or shipment.
Moreover, in the normal assembly operation of the overcap to a bottle neck, the overcap is heat fused to the bottle neck to form the hermetic seal. It is necessary that the overcap be accessible to the heat and pressure die during assembly. Thus difficulty would be experienced if the outer ring were assembled to the overcap prior to sealing on the container, and the outer ring is commonly assembled after installation of the overcap on the container.